A number of applications continue to drive the need for high-speed data transport. Industry specific examples include remote film editing, medical image transport, and financial service data consolidation and backup. Business communications and training further accelerate information transfer needs across all sectors. As business, government and educational institutions disseminate more information, greater importance is attached to data transfer. In this environment, reliable, high-speed video and data transport becomes even more critical.
Furthermore, a tremendous growth in Internet traffic has caused a strain on the capacity of telephony networks. Network shortcomings include network outages, insufficient access bandwidth, and insufficient internode bandwidth. Currently, providers need to make significant investments, as well as experience installation delays, to upgrade network infrastructure, yet they cannot pass the costs on to the end users.
Corporate LANs/WANs also generate an insatiable demand for higher bandwidth. The demand for bandwidth goes up as more and more users are connected. The users, in turn, demand more services and improved network speed. Personal computers are being used to process not only text, but graphics and video as well, all on networks that are increasingly global. Widespread implementation of corporate intranets and extranets further drive the move to increased bandwidth applications. High-speed networking is also driven by the growth of video distribution, client/server technology, decentralized systems, increased processing power and developments in storage capacity.
To meet the high demand, networks of satellites are used to provide varied coverage as well as provide capacity. These satellites may be in geostationary, middle or low earth orbit. In many systems, not all the satellites are used to capacity at any given time.
Another drawback to various networks is that the life cycle of a network may exceed 10-15 years. During the life of the network, the needs of users will most likely change, but due to lack of flexibility of the electronics, the system may not be able to address all of the new user needs. Therefore, more satellites may have to be launched or the system will remain inadequate.
Known systems are typically deployed with little internal flexibility to accommodate changing requirements over the life of the system. Also, if a satellite within the system fails, service may be interrupted. Other satellites in the network may be called upon to provide back-up. However, some net loss in service is likely since the electronic payload may not be configurable to match the service provided by the failed satellite. If, however, the payload characteristics do not match, then, a net loss of overall service capacity will result.
A system such as that disclosed in commonly owned co-pending patent application Ser. Nos. 08/867,672 and 09/159,332 have fixed spot beams and scanned spot beams. The beams are reconfigured to provide satellite coverage to various areas upon the earth. By changing the phase and amplitude coefficients, various spot beam areas of coverage may be configured. One drawback to such a system is that other system parameters such as the communication frequencies are generally fixed in the satellite. Thus, the satellite is not usable for other satellites within the system.
It would therefore be desirable to provide a satellite-based communications system capable of minimizing service coverage loss within a satellite system if a satellite fails. It would further be desirable to provide a satellite with the capability to be reconfigured over the life of the satellite to meet the changing requirements of system users.